This application claims priority of Taiwan Patent Application Ser. No. 90113946 filed on Jun. 8, 2001.
The present invention generally relates to a key device for a keyboard and to an assembling method thereof.
Scissors-like structures are widely used in low-profile key devices such as keyboards. Referring to FIG. 1a, a first frame 101 and a second frame 102 may be assembled to form a scissors-like structure. Two shafts 103 are respectively disposed on the outer surfaces of first frame 101, and axes of two shafts 103 may be aligned in a line as shown. Two slots 104 are respectively provided on inner surfaces of the frame 102, and axes of two slots 104 are aligned as shown. Two shafts 103 and two slots 104 are rotatably connected to each other to form a scissors-like structure. The scissors-like structure is connected to a keycap 107 and a base 108, as shown in FIG. 1b. 
Referring to FIG. 1b, first frame 101 has two outer surfaces 105, 105xe2x80x2 and second frame 102 has two inner surfaces 106, 106xe2x80x2. The distance between outer surfaces 105, 105xe2x80x2 is typically about equal to the distance between inner surfaces 106, 106xe2x80x2. When shafts 103 are disposed into slots 104, first frame 101 is suitably compressed to shorten the span of the first frame 101 along axial direction A-Axe2x80x2, or the second frame 102 has to be expended to lengthen the span of the second frame 102 along direction A-Axe2x80x2. In other words, one of two frames 101 or 102 appropriately deforms its shape during assembly. It is typically desired to minimize deformation of the frames during assembly to prevent breakage and to strengthen the key structure. One solution is to shorten the length of the shafts 103, although this results in a less-stable key structure.
The reliability of scissors-like structure 100 typically depends on an effective length of the shaft 103. The effective length of the shaft 103 is defined as the length carrying radial force after the shafts 103 and the slots 104 are assembled together. If the effective length of the shaft 103 is shortened, the reliability of scissors-like structure decreases. For example, when a user detaches the keycap 107 from the structure, a shorter shaft 103 may escape from slot 104 and frames 101 and 102 may become separated.
Ease of assembly and reliability of a key device do not coexist in the prior art. A demand for a key device with these characteristics therefore exists.
One aspect of the present invention is to provide a key device which gives consideration to assembly convenience and reliability.
Another aspect of the present invention is to provide a method for assembling the key device.
An exemplary key device of the present invention includes first and second arms.
The first arm has a shaft and the second arm has a slot with an open first end and a closed second end. The first and second portions are connected to each other, and the second portion define an axial direction. The first and second arms are rotatably assembled to form a scissors-like structure. When the shaft is in the first portion of the slot, the shaft can slide and rotate. When the shaft is the second portion of the slot, the shaft can rotate but not slide.
An assembling method for the key device is also provided in the present invention. The key device includes a first and second arms. The first arm has a shaft and the second arm has a slot with an open first end and a closed second end. The first and second portions are connected to each other, and the second portion define an axial direction. The method includes the steps of disposing the shaft into the first portion via the open first end. The shaft slides along the first portion. Finally, when the shaft and second portion are substantially in a line, the shaft is pushed into the second portion along the axial direction.